<?xml version="1.0"?>

<configuration>

  <configSections/>

  <appSettings>

    <add key="fileUploadPath" value="~/Uploads"/>

    <add key="maxFileSizeLimit" value="4194304"/>

    <add key="bufferSize" value="16384"/>

    <add key="allowedMIMEType" value="*"/>

  </appSettings>

  <connectionStrings/>

  <system.web>

    <httpModules>

      <add name="IGUploadModule" type="Infragistics.Web.UI.EditorControls.UploadModule"/>

    </httpModules>

    <httpHandlers>

      <add path="IGUploadStatusHandler.ashx" verb="GET" type="Infragistics.Web.UI.EditorControls.UploadStatusHandler" validate="true"/>

    </httpHandlers>

    <customErrors mode="Off" redirectMode="ResponseRewrite" defaultRedirect="~/Default.aspx?error=1"/>

    <compilation debug="true" targetFramework="4.0">

      <assemblies>

        <add assembly="System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089"/>

        <add assembly="System.Design, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B03F5F7F11D50A3A"/>

        <add assembly="Infragistics4.Web.v11.2, Version=11.2.20112.2055, Culture=neutral, PublicKeyToken=7DD5C3163F2CD0CB"/>

        <add assembly="Infragistics4.Web.jQuery.v11.2, Version=11.2.20112.2055, Culture=neutral, PublicKeyToken=7DD5C3163F2CD0CB"/>

        <add assembly="Infragistics4.WebUI.Documents.Reports.v11.2, Version=11.2.20112.2055, Culture=neutral, PublicKeyToken=7DD5C3163F2CD0CB"/>

        <add assembly="Infragistics4.WebUI.Documents.Excel.v11.2, Version=11.2.20112.2055, Culture=neutral, PublicKeyToken=7DD5C3163F2CD0CB"/>

        <add assembly="Infragistics4.WebUI.Documents.Word.v11.2, Version=11.2.20112.2055, Culture=neutral, PublicKeyToken=7DD5C3163F2CD0CB"/>

        <add assembly="Infragistics4.WebUI.Documents.IO.v11.2, Version=11.2.20112.2055, Culture=neutral, PublicKeyToken=7DD5C3163F2CD0CB"/>

      </assemblies>

    </compilation>

    <!--

            The <authentication> section enables configuration 

            of the security authentication mode used by 

            ASP.NET to identify an incoming user. 

        -->

    <authentication mode="Windows"/>

    <!--

            The <customErrors> section enables configuration 

            of what to do if/when an unhandled error occurs 

            during the execution of a request. Specifically, 

            it enables developers to configure html error pages 

            to be displayed in place of a error stack trace.

        <customErrors mode="RemoteOnly" defaultRedirect="GenericErrorPage.htm">

            <error statusCode="403" redirect="NoAccess.htm" />

            <error statusCode="404" redirect="FileNotFound.htm" />

        </customErrors>

        -->

    <pages controlRenderingCompatibilityVersion="3.5" clientIDMode="AutoID"/>

  </system.web>

  <system.webServer>

    <modules runAllManagedModulesForAllRequests="true">

      <add name="IGUploadModule"

           type="Infragisitcs.Web.UI.EditorControls.UploadModule"

           preCondition="managedHandler" />

    </modules>

    <handlers>

      <add name="IGUploadStatusHandler" path="IGUploadStatusHandler.ashx"

           verb="*" type=" Infragistics.Web.UI.EditorControls.UploadStatusHandler"

           preCondition="integratedMode" />

    </handlers>

  </system.webServer>

  <!-- 

        The system.webServer section is required for running ASP.NET AJAX under Internet

        Information Services 7.0.  It is not necessary for previous version of IIS.

    -->

</configuration>

I suppose you have not registerred assemblies in GAC or you have not set them in bin folder of your application. Please check this. Also you can try with our samples: for instance you can check this link http://samples.infragistics.com/aspnet/Samples/WebUpload/Display/MultipleUpload/Default.aspx?cn=web-upload&sid=a8c69ee2-99e1-4512-938b-52c5d0b9cb6f and also to download our samples and run them.

Thanks,

Miro Hristov